Effect of Recombinant NGF Encapsulated in Chitosan on Rabbit Sperm Traits and Main Metabolic Pathways

Area of Science:

• Reproductive biology and molecular signaling.
• Biomaterials for drug delivery.
• Sperm physiology and cryopreservation.

Background:

• Nerve Growth Factor (NGF) plays roles in neuronal development and survival.
• Chitosan is a biocompatible polymer used for encapsulating therapeutic agents.
• Understanding sperm functional parameters is crucial for assisted reproduction.

Purpose of the Study:

• To investigate the effects of chitosan-encapsulated recombinant rabbit NGF (rrβNGFch) on sperm parameters.
• To analyze the involvement of specific intracellular signaling pathways (AKT, ERK1/2, JNK) in response to rrβNGFch.
• To evaluate the impact of storage duration on sperm quality under rrβNGFch treatment.

Main Methods:

• Sperm samples were treated with rrβNGFch and stored for 30 min and 2 h.
• Sperm viability, motility, kinetic traits, capacitation, acrosome reaction (AR), and apoptosis were assessed.
• Intracellular signaling pathway activation (AKT, ERK1/2, JNK) was analyzed using molecular techniques.

Main Results:

• rrβNGFch treatment positively influenced sperm capacitation and AR, especially at shorter storage times.
• Extended storage (2 h) significantly reduced all measured sperm quality parameters.
• ERK1/2 activation correlated with capacitation, AR, and apoptosis, suggesting its role as an NGF downstream mediator.
• AKT and JNK pathways did not show treatment-dependent activation or correlation with functional sperm traits.

Conclusions:

• rrβNGFch shows potential for promoting functional sperm activation, particularly in early incubation stages.
• The observed improvements in capacitation and AR were not directly linked to AKT or JNK signaling.
• Prolonged storage poses a significant challenge to sperm quality, irrespective of NGF treatment.
• Further research into NGF's molecular mechanisms in sperm and its application in assisted reproduction is warranted.